As anti-American furor raged in the home of the Arab Spring, the top U.S. diplomat on Friday sternly warned countries where the unrest has been most pronounced: Stop the violence and seek justice against those attacking diplomatic missions, or else the United States will.

From Morocco to Malaysia, thousands of Muslims have taken to the streets in recent days.

Many have fumed over what Secretary of State Hillary Clinton described Friday as an "awful Internet video that we had nothing to do with" -- an inflammatory anti-Islam film posted online this summer, and publicized in recent days.

The 14-minute film trailer, which was privately produced in the United States led by a man federal officials identified as Nakoula Basseley Nakoula, mocks the Prophet Mohammed as a womanizer, child molester and ruthless killer.

Protesters, notably, haven't all been violent and they represent a fraction of their respective nations' populations: In Egypt, for example, a few thousand have clashed with security forces outside the U.S. embassy in Cairo, in a nation of more than 80 million people.

Still, confrontations that have occurred have aggravated relations between the U.S. and other nations, and led to a number of deaths -- including those of the U.S. ambassador to Libya and three others killed in an attack Tuesday in Benghazi, Libya. The U.N. Security Council issued a statement Friday expressing "deep concern" over attacks on diplomatic posts, calling them "unjustifiable regardless of their motivations."

Clinton said such assaults are misguided, and fly in the face of the better society many in these countries recently fought for when they overthrew authoritarian rulers.

"The people of Egypt, Libya, Yemen and Tunisia did not trade the tyranny of a dictator for the tyranny of a mob," she said Friday during a ceremony in which the bodies of the four killed in Benghazi returned to the United States.

"Reasonable people and responsible leaders in these countries need to do everything they can to restore security and hold accountable those behind these violent acts. And we will ... keep taking steps to protect our personnel around the world."

The contrast between then and now was especially evident in Tunisia, birthplace of the Arab Spring.

Two years ago, the self-immolation of street vendor Mohamed Bouazizi set off a wave of popular unrest that soon led to the downfall of Tunisia's longtime leader, President Zine El Abidine Ben Ali.

On Friday, hundreds of demonstrators -- some belonging to the Salafi movement -- were back on the streets of Tunis, setting their sights on the U.S. Embassy.

They burned cars, praised late al Qaeda leader Osama bin Laden, stormed the embassy complex and replaced the U.S. flag with their own black banner, according to witness accounts. A nearby American school was "unusable" after being badly damaged, U.S. State Department spokeswoman Victoria Nuland said.

Two people were killed and more than 20 were wounded, interim Tunisian President Al-Munsif Al-Marzouki said late Friday on state-run TV.

While asserting the anti-Islam video that stirred the outrage "cannot be justified by claims of freedom of opinion and speech" (and adding Tunisia would try to sue the filmmaker), al-Marzouki condemned the "irresponsible, unjustified acts of violence by protesters" who wrongly blamed the U.S. government for the film.

Anti-American protests -- some peaceful, some violent -- were hardly confined to Tunisia. Here's a breakdown of events Friday around the Muslim world:

-- In the Egyptian capital of Cairo, a running battle between police and protesters continued into its fourth day. There was a peaceful demonstration at Tahrir Square, but unrest erupted outside the U.S. Embassy as riot police continued to clash sporadically with protesters.

The Interior Ministry issued a statement saying 53 security officers were injured Friday, seven by birdshot. And birdshot was blamed for the death Friday of one protester, whom the Egyptian ministry described as an ex-convict with an extensive criminal record. Thirty of the 142 people arrested since the unrest began Tuesday remain in custody.

-- In Egypt's northern Sinai, Islamist Bedouins staged a protest, a security official said. Militants carrying automatic weapons breached a base housing international peacekeeping troops and burned trucks and a watch tower. The armed clashes injured at least four troops and an Islamist Bedouin. The 1,500-troop mission has supervised the security of the Egyptian-Israeli peace treaty since 1979.

-- In Sudan's capital, Khartoum, protesters managed to get inside the compound containing the German and British embassies. They did not breach the British building, but some got into a German Embassy and pulled down a German flag before police with tear gas forced the crowds to retreat.